Angle block and method of manufacture



June 24, 1952 R. J. RAHN ET Ax. 2,601,630

ANGLE BLOCK AND METHOD 0F' MANUFACTURE Filed July 2. 1947 3 Sheets-Sheet l %/O Mun. mh.

'IHM I. (O 6/ Ziff-ji* e N I M I 'f n" MW' m ,MINIMUM ,5 i I ,f I

WAN Lf @AH/Y @Ummm/JAHN June 24, 1952 R. J. RAHNj-:r AL 2,601,630

ANGLE BLOCK AND METHOD OF' MANUFACTURE Filed July 2. 1947 s sheets-shewb z I VAN J PAH/Y PUDOLDH d PAH/Y Y :im l(uJulwsm June 24, 1952 R. J. RAHN l-:T AL 2,601,630

ANGLE BLOCK AND METHOD OF MANUFACTURE Filed July 2. 1947 3 Sheets-Sheet 5 Patented June 24, 1952 BLOCK AND ME'rnon yor i MANUFACTURE Rudolph J .f 'Rahn and .Ivan J. Rahn. Dayton, (Jliio l Application July 2, 1947,'-Sera.l-No.158,65 8

comms. (c1. l.s1-115165 "Ifhis invention pertains .to :precision angle blocks ,for ,gaging and 1test zpurposes, :the inventive -conception auf making- .fsuch tesi;v gages fronti va natural granite rock, and the herein .described method of reducing a 'body Aof stock material to accurately contoured form. While Various forms of granite rock may be utilized, y-which are known in l:different localities under various designations, an igneous rock, known commercially `as fb'lack granite is `a preferred form.

Angle blocks and surface 1plates with which Athey cooperate, have ordinarily been made from metal, but have been found subect to :many -o'b jectionable and Aundesirable characteristics. 2inc-luding lwear, warping, corrosionand rust,.change of shape and loss o-f accuracy.- -A-n .extremely hard.' impervious, non absorbingstone .such as ligneo-us rock has been foundgreatl-y superior and more desirable for such purpose. The igneous black granite is 'some 4times known lunder other circumstances, vlas diaba'se, diorli'te or gab-bro.

Being, presumably, of volcanic origin and fhavingbee'n aged Afor-millions of years under 'conditions of `heat `and spressure such-rock materia-lhas Ibeent-horoughly seasoned and relieved-of .internal stresses and strains, 'the material is `qui-tev -stable and will not Warp nor changel its-shape under -inuence of shock or change of 4-temjperatlne or climatic conditions. Such' granite which is harder than tool steel is permanent and will 1re tain the accuracy of the gages and -test elements rformed therefrom and will not ibecom'e charged with abrasive. `While :the presen-t inventive conceptionof utili zation of natural granite rockandfespeciafllykthat of igneous character for productionzoffaccurately vsurfaced :angular gage .and test fblocks-and of fthe Vsurface y,plates with :which they are usabile, wolves `distinctive change .of :material from that which :gage .and test lelements have heretofore 'been made, it is a ,change vwhich :is :productive .of greatly improvedresults and much *longer lasting accuracy.

The object of the iinuentioniis Lto .provide `angle fbrlocks, gageand test elements by `an `improved method .of @procedure :by gaga-and stestele- `truents :not only may be :economically .manufacatured :but will ibe more .efficient andcf .increased accuracy in use, .of greater '.durability, possessing a high .degree of smoothness, o iering minimum resistance :toimovement .of `the iblocks or of struments vthereon, and unlikely .to fget out of repair. l l l yA rurther object is to form `such gage and test elements from fa substance in Afw-hich abrasivemai 2 terial Wiilnpt becomeembeddedand thus acquire .lapmngnroperties .A funtheriobject of :the invention .is the :utilization-.of a non-rusting substance landthe .complete elimination of high or low spots resulting .from .accumulation .or removal :of rust deposits as .occursen metal elements.

:A iur-ther n'bject fof the .invention is the utiliza,- tion .of .a substance which will fbe substantially constant will .not-change its-form Aor loose fits iaccuracy incident .to ishock or a yiolent :bump occurring during shipment, A.which induce warpage.

A further advantage is that in event .of accidental formation of afdent :by alblow .or violent shock, :a compensatory swelling Aor elevation .of the adjacent surtace, incident .to dis-placementcf material will not occur-vas results from such indentation fin a .metal surface, .thus destroying --the accuracy lof a planar race. i

`ilfurther object-of the Linvention the production :of gage and test elements .from a material possessing the Aadvantageous structural advantages, Athe inherent meritorious vcha-racteristics and the mode of production herein described yor `their equivalents.

"With the above primary `and other `incidental objects 1n view as -Wil-l more fully vappear in the specification, ythe invention intended to be pro- Ltected by Letters Patent consists -of the features of construction, the parts and --combinaticns thereof, `and -the imode -of operation, as hereinafter described -o-r illustrated in ythe accom-panying-drawingsor-theirequivalents.

In :the drawings, shown for illustrative purvnoses:

Fig. l1 Vis a '-perspectivef'view of a :surface plate and a cooperating `angle block resting thereon constructed Ifrom igneous stone, embodying `the present invention.

Fig. 4"2 illustrates three finished angular-gage 'blocks-'the risilzrle vertical races and the underlying V@horizontal finished planar faces of @which are disposed at :right angles to each other.

rFig 'B'illustrates a side elevation of -a pair-'of gage-blocks narranged in cooperative relation with Aa surface pla-te comprising a step 'in the generation of accurately dsposedfacesupon theblocks.

Fig. 4 Lis a #similar Niewshowing arrangement of another -pair of gage'bloeks illustrating aiurther step in the process `of development of angularly disposedfacestherecn.

=Fig.`^5 is fa succeeding like view of a different of the series -of blocks, `showing a -further step in 'the vangular face development.

.face plate I0.

Figs. 6 and 7 are side elevations illustrating different modes of testing the accuracy of the horizontal and the vertical faces respectively of gage blocks and their angularity in relation to an accurately finished surface plate, by application of a surface test indicator.

Fig. 8 illustrates a further mode of testing the accuracy of a planar surface of a block or plate by application of a surface test indicator, in different relation from that shown in the preceding figures. i

Like parts are indicated by similar characters of reference throughout the several views.

Referring to the drawings, I is a conventional surface plate ordinarily constructed from steel, but which in the present instance is formed from the igneous stone hereinbefore mentioned, preferably, but not necessarily, that commercially known as black granite. The top face of the surface plate I0 is reduced to a true planar surface. The linear margins of the plate Il) are under cut at II to afford clamping lips I3 on opposite sides, or if desired on all four sides, for temporary attachment of work pieces or instruments.

In producing the angle blocks I4 of granite or igneous rock, one face I5 of each block, preferablybut not necessarily, that of larger area, is 'rst reduced to a planar surface. Toassure accuracyf the faces I5 of multiple blocks I`4 are lapped successively one upon another, preferably in setsof three blocks, using therebetween abrasives of progressively decreasing degrees of fine- -ness until the desired accuracy is attained. The

remaining unfinished faces I6 are roughly reduced to symmetrical relation by surface grind- .ing which removes excess material more rapidly gutter or channel I8 in overlapping relation withl the surface I'I of the block to be flnished.- The blockjI4 secured with its planar finished face I5 in contact with the finished face of the sur- A mixture of abrasive in Water is spread evenly upon the uppermost face I1 of theattached block No. 2 andupon the correspondingfunder face lof a second block No. 1. The surface` plate I0 with its gutter or channel I8 extending across the plane of contact between theblocks, is tipped or inclined at approximately thirty degrees (30) to the vertical. The angle of :the surface plate and the blocks I4 Vthereon maybe varied through a rather wide range, sufficient that ythe movable block I4, shown as No. 1, Fig. 3, will exert sufficient pressureV by gravity upon the surface plate to accurately conform to andfbev guided thereby. The superposed angle block,jNo.-1 of Fig. 3, is then moved to and-fro with its under face I1 sliding backy and forth upon the uppermost face II of the stationary block No. 2 until the lrespective faces are reducedby the interposed abrasive until they make complete contact. 'Ijhe excess slurry or abrasive working from between the blocks is, received in the transverse channel or groove` III thus preventing its entryV between the face= I'5 4of the sliding block No. 1 and the face of the surface plate. The angularity of the plane of contact preliminarily produced may depend somewhat upon the accuracy of the initial rough grinding. However 4 the surface II produced upon one of the blocks by this process may be obtuse while that upon the other of the blocks may be acute, the respective angles being supplementary, totaling one hundred and eighty degrees. Thereafter as in Fig. 4, the block No. 3 may be fixedly clamped to the surface plate and the block No. 2 superposed thereupon `with abrasive between. By rubbing the uppermost block No. 2, to and fro, the obtuse or acute angularity of the block No. 2, Whichever it may be, is reduced to somewhat less angularity than before, and the corresponding upturned face of block No. 3 will be preliminarily surfaced.

I5 in contact with the surface plate and the block No. l3 is superposed thereonI as illustrated in Fig. 5, and the process repeated. The angular relation of thev faces I1 when initially interen- .gaged may be both obtuse or both acute. After being abraded one upon the other, the high portions of each will be worn down and both blocks will -approach a common face by changing the acuity or obtuseness thereof as the case may be. The straight line to and fro abrasion of-one block upon another while their previously finished faces I5 ,are guided by the face of the surface plate may develop longitudinal ridges on the faces being produced. To remove such ridges each pair of blocks before being rearranged in different pairs is lapped together again intermediate succeeding to and fro abrading operation with a circular motion, after being removed fromA engagement with the surface plate. This further operation is conducted in the usual manner of producing planar faces as in the production of the initial faces I5 and face of the surface plate. p i Y.

. By this sequence the face I1 of each block` is subjected twice to abrasion or rubbing, each time with a different one of the remaining blocks of thel series. `This sequence of operations illustrated inFigs. 3, 4, and 5 is repeated over and over y again with progressively ner abrasives therebetween until the desired degree of accuracy is achieved.

Finally the angular faces I'I of the respective blocks will assume right angle relation to their faces I5;

If so desired other faces I6 of the blocks may likewise be finished atninety degrees (90) to previously developed faces by securing finished faces V,in contact with the surface plate and repeating the process.

In event an. `angle of less than ninety degrees (90) is'desired a plate having an angle of twice the difference of the. degree of the face to be produced and ninety degrees is inserted between the finished face of one of the angle blocks and the surface plate. For example if the face I1Y is to` 'be developed at an angle of eighty degrees to the face I5. `a plate or shim of twenty degrees angularity is inserted. The abrasive action of eachof three blocks upon veach ofthe other two blocks so mounted will result in bisecting the remaining angle of one hundred and sixty degrees (160) and the faces developed on each of the blocks will be of eighty degrees (80) instead of ninety degrees Obviously the accuracyof the developed angles will'dep'end somewhat upon that cfV the inserted shim or plate. To test the accuracy of the ninety degree relation of the finished faces, one of the angle blocks is yclamped with its face I'I contacting `the face lThereafter' the block No. 1 is stationarily clamped with its initial accurately surfaced face predetermined anglev to the planar face of the second block and that of the surface plate.

.6. A pair of stone blocks, each having a. planar face, an inclined surface plate in contacting relation with the face of which the planar faces of REFERENCES CITED The following references are ofrecord in the le of this patent:

` UNITED STATES PATENTS Number Name Date Fiske Dec. 31, '1889 Number 8 Namel Y Date Eaton Apr. 2, 1918 Hoke Mar. 1l, 1924 Hoke Mar. 11, 1924 Hoke Apr. 22, 1924 Weaver July 22, 1924 Hoke Nov. 4, 1924 Stanforth Feb. 21, 1928 Firestein May 2, 1933 Reich `May 21, 1940 Tillyer. Oct. 31, 1944 Hawkins Feb. l2, 1946 Crowley Oct. 8, 1946 Hall Nov. 12, 1946 McLeod et al May 13, 1947 Overzat June 15, 1948 OTHER REFERENCES Amateur Telescope Making, Munn and C0.,

4th edition, 1935, pp. 57 and 58.

. Amateur Telescope Making, Advanced, Munn and C0.. 194s, page 116. 

